Scuba diving masks typically comprise a frame to which one or two lenses are attached by way of a watertight seal. A soft facepiece extends from an edge of the frame to create a seal with a diver's face. A flexible strap is also provided, the ends of which are connected to opposing sides of the frame. The length of the strap is usually adjustable so as to exert sufficient tension and, thereby, ensure relatively stable positioning of the facepiece on the diver's face and adequate watertightness.
The length of the strap is usually adjusted using a buckle. Although useful, buckles have been found impractical, especially when the diver is wearing gloves, or has cold and/or wet hands. Another common approach is to provide fasteners that enable the length of the strap to be varied without the necessity of having the diver take off his or her mask. One solution has been to provide a strap with ends that wrap around pivots on fork-shaped side portions of the mask. The strap has transverse stop ribbing operatively engaged with a stop tooth projecting from a lever which is, in turn, pressed elastically against the ribs. Upon overcoming the elastic resistance created, the lever may then be raised by the user, thereby, enabling the strap to slide to a new position, without removing the mask from the user's face. The elastic resistance is provided by a spring in some arrangements, whereas in others the lever itself is utilized, the lever being flexed in order to detach the tooth from the strap and, thereby, enable the latter to slide. Although the foregoing approaches do not require that the mask be removed, adjustment of the strap has remained difficult and uncomfortable, especially when done with cold and/or wet hands. Moreover, strap adjustment cannot be done while the diver is wearing gloves since a finger tip is needed to lift the lever attached to the stop tooth which engages the strap's ribbing.
In another arrangement, a compact device is provided for varying the length of a strap suitable for use on swimming goggles. This device comprises a stop lever and a tooth extending from the lever. The lever engages a rib on the strap which is wrapped about an underlying pivot and integrally attached to a side portion of the goggles' frame. The lever includes a first arm, preferably in the form of a fork, with a first end pivotally connected to the side portion and a second end abutting the bottom of a seat in the side portion. In addition, a second arm is provided from which the tooth extends transversely, the second arm having a free first end for operation and a second end rigidly connected to the second end of the first arm. The second arm is desirably a tongue extending cantilevered from and coplanar with the fork that forms the first arm. The second arm also has a raised portion at its free end that may be used to lift the tongue, disengage the transverse tooth from the rib on the strap, and thereby allow the arm to slide. While this arrangement is beneficial, the stop lever has been found relatively difficult to operate.
Another drawback of this approach is that the lever has been found difficult to operate.